This invention relates generally to a moving carriage and, more particularly, to a carriage for providing high precision parallel plane translational movement to a device such as a mirror in a Michelson interferometer.
During use of a Michelson interferometer, a mirror is translated through planes which are at least approximately parallel to each other. The accuracy provided by the instrument is directly related to the degree of parallelism in the movement of the mirror. Precision bearing way systems are commonly employed to achieve the parallel translation of the mirror. Such bearing way systems commonly employ sliding flat surfaces or circular rolling elements either of which require lubrication. In many cases, such as, for example, cryogenic applications, the requirement for lubrication is an undesirable restriction.
Other known types of Michelson interferometer carriage systems utilize linkages as an alternative to conventional way systems. For example, hinged parallelograms have been used to provide parallel and nearly linear translation of a movable mirror. Such linkage systems are disclosed, for example, in U.S. Pat. No. 4,789,125. By employing crossed flat spring pivots, known as flex pivots, lubrication requirements can be alleviated in a hinged parallelogram carriage system. However, such linkages generally introduce more tilt into the movable mirror motion than do precision ground way systems.
The object of this invention, therefore, is to provide an improved Michelson interferometer mirror carriage that will provide highly accurate parallel plane translational mirror motion without a requirement for lubrication.